The invention relates to a guide wire that is intended for a medical instrument and that exhibits a marking pattern which extends over at least a part of the axial length of the guide wire and comprises detectable markings of a plurality of different types of markings.
Guide wires of this type are used especially in surgical instruments, like endoscopes. The marking pattern serves to make it easier to detect the momentary position of the guide wire in use, to which end the markings can be detected, for example, by eye or by X-rays.
In addition, it is known to construct the marking pattern of at least two different marking rings that follow one after the other alternatingly in the longitudinal direction of the guide wire and extend over the entire circumferential length of the guide wire. This marking pattern makes it possible to perceive the axial motion and/or the feed motion of the guide wire from the sequence of marking rings that alternate—for example, varying in brightness—in the axial direction of the wire.
In order to detect, in addition to the axial motion, also a rotational motion of the guide wire by sensing the marking pattern, it is known to provide a marking pattern composed of at least two marking spirals that are arranged with alternating windings. This pattern can be achieved, for example, with a background color on the periphery of the guide wire and a helical strip of a contrasting color that is applied on said periphery, as disclosed in the patent specification EP 0 714 315 B1. The published patent application DE 198 23 414 A1 shows an alternative implementation, where a plurality of different helical spring members with alternating windings are inter-wound and provide their own marking externally, so that the result is altogether two or more different, detectable marking spirals.
The known marking patterns with marking spirals are not always easy to produce. In addition, there may be detection problems when the guide wire performs a combined axial and rotational motion that matches to a high degree the course of the marking spirals because then it is not very likely that the defined detection point will show the marking change-over that signals the motion.
The patent specification DE 102 43 261 B4 discloses a guide wire that makes it possible to detect the motion of the guide wire not only during pure axial or rotational motions but also during combined axial and rotational motions. In order to achieve this goal, the markings of the guide wire are configured in such a way that the markings of at least a first of many different marking types are formed by marking surfaces that extend only over a part of the circumferential length of the guide wire and only over a part of the axial length of the marking pattern and follow one after the other in the axial direction of the guide wire with an offset in the circumferential direction and/or with axial spacing.
Working on this basis, the published patent application DE 102 55 030 A1 proposes that the markings of at least two different marking types be configured as the marking surfaces that extend only over a part of the circumferential length of the guide wire and only over a part of the axial length of the marking pattern and follow one after the other in the axial direction of the guide wire with an offset in the circumferential direction and/or with axial spacing.
The invention is based on the technical problem of providing a guide wire of the type described above such that its marking pattern further facilitates the detection of the motion of the guide wire as compared to the aforementioned prior art.
The invention solves this problem by providing a guide wire that is intended for a medical instrument and that comprises a marking pattern, which extends over at least a part of the axial length of the guide wire and comprises detectable markings of at least three different types of markings. Markings of a first and second marking type are formed by the marking surfaces, of which the marking surfaces of at least the first marking type extend only over a part of the circumferential length of the guide wire and only over a part of the axial length of the marking pattern and follow one after the other in the axial direction of the guide wire with spacing by at least one intermediate marking surface of the second marking type. At least one longitudinal marking strip is formed as a marking of a third marking type, which extends continuously over the axial length of the marking pattern.
The invention also solves this problem by providing a guide wire that is intended for a medical instrument and that comprises a marking pattern, which extends over at least a part of the axial length of the guide wire and comprises detectable markings of at least two different types of markings. Markings of a first marking type are formed by transverse strip structures, which can be distinguished from each other and are arranged with axial spacing in relation to each other and extend over more than half the guide wire circumference in the circumferential direction. Markings of a second marking type are provided in the form of marking surfaces and/or longitudinal marking strips in at least the area between each pair of transverse strip structures, wherein the marking surfaces extend only over a part of the circumferential length of the guide wire and only over a part of the axial length of the marking pattern and follow one after the other in the axial direction of the guide wire with an offset in the circumferential direction and/or with axial spacing, or the longitudinal marking strips extend continuously between the transverse strip structures.
In one embodiment, the guide wire, according to the invention, has detectable markings of at least three different marking types, two of which are achieved by marking surfaces that are arranged in a special way that makes it possible to perceive the axial motions of the guide wire. In this case these marking surfaces can also contribute to the detection of the rotational position of the guide wire. With respect to the properties and the advantages of the marking surfaces of the first and the second marking type reference can also be made to the aforementioned documents DE 102 43 261 B4 and DE 102 55 030 A1, which describe the respective guide wires that exhibit such types of marking surfaces. In addition, the detection of the rotational position is facilitated in that at least one longitudinal marking strip is formed as a third marking type that extends continuously over the axial length of the marking pattern.
In a further development of the invention, the marking surfaces of the first and/or second marking type are formed by ring segment marking surfaces that are rectangular, diamond shaped or circular in the circumferential development of the guide wire, that is, by means of geometric pattern elements that are easy to detect and simple to produce. In this context the term “circular” comprises not only round surfaces, but also elliptical, oval and similar surfaces. In an additional embodiment, the marking surfaces of the first and the second marking type are formed by the respective ring segment marking surfaces that exhibit a definable expansion in the circumferential and axial direction of the guide wire and are arranged so as to alternate in the axial direction of the guide wire, a feature that makes it possible to detect the axial position of the guide wire in an advantageous way. Even the detection of the rotational position of the guide wire can be facilitated by the respective arrangement of the ring segment marking surfaces, for example, in that in an embodiment of the invention, the ring segment marking surfaces of the respective marking type are arranged with an offset in the circumferential direction.
The longitudinal marking strip(s) can extend, without or with the circumferential direction component—that is, in exactly the axial direction or as an alternative at an oblique angle thereto and/or in the form of a helical line with a more or less large circumferential direction component.
In a further development of the invention, a plurality of longitudinal marking strips are arranged so as to be spaced apart in the circumferential direction, and the marking surfaces of the first and the second marking type are located between the longitudinal marking strips. Such a marking pattern facilitates even more the detection of the axial and rotational position of the guide wire.
In a further development of the invention, the markings of the first, second and/or third marking type can be detected by eye or by X-rays. In particular, it can be provided that one of the marking types can be detected visually, and another marking type can be detected by X-rays, for example, by providing visually detectable marking surfaces and one or more radiographically detectable longitudinal marking strips.
In a further development of the invention, the longitudinal marking strip(s) is (are) integrated into a sheathing of a core wire of the guide wire by using a suitably detectable material for the sheathing in a peripheral area forming the longitudinal marking strip(s). In this case the material is different from the material(s) for the remaining area of the sheathing. This feature allows the longitudinal marking strip(s) to be produced in an advantageous way even from a manufacturing viewpoint, for example, when they are provided as radiographically detectable longitudinal strips.
In an additional embodiment of this technique, the sheathing in a distal end section of the guide wire is formed with a larger cross sectional area than in an adjoining section, as a result of which a tapering of the core wire in this distal end section is compensated at least partially with respect to the outside diameter of the guide wire. Then the at least one longitudinal marking strip exhibits in the distal end section a larger cross sectional area than in its adjoining guide wire section, a feature that can be used, for example, for an improved radiographic visibility of the distal end section of the guide wire.
In the case of the guide wire according to another embodiment, markings of a first marking type in the form of transverse strip structures are combined with markings of a second marking type in the form of marking surfaces or longitudinal marking strips in the area between each pair of transverse strip structures.
In this case the marking surfaces extend only over a part of the circumferential surface of the guide wire and only over a part of the axial length of the marking pattern and follow one after the other in the axial direction of the guide wire with an offset in the circumferential direction and/or with axial spacing, or the longitudinal marking strips extend continuously between the transverse strip structures. The transverse strip structures can be distinguished from each other and arranged so as to be axially spaced apart from each other and extend over more than half of the guide wire periphery in the circumferential direction. Even this marking pattern is capable of improving in an advantageous way the detection of the axial and rotational position of the guide wire. With respect to these properties and advantages of the marking surfaces reference can be made in turn to the aforementioned publications DE 102 43 261 B4 and DE 102 55 030 A1. The additional transverse strip structures facilitate to a high degree the detection of the axial position of the guide wire.
In a further development of the invention, the differentiable transverse strip structures are formed in an advantageous way in terms of production engineering by use of a varying number of closely adjacent individual strips.
In a further development of the invention, the marking surfaces are formed by ring segment marking surfaces that are rectangular, diamond shaped, oval or circular in the circumferential development of the guide wire, where with respect to their properties and advantages reference is made to the above description. In this respect the marking surfaces can be configured so as to cover the whole surface area or the grooved area.
In a further development of the invention, a plurality of longitudinal marking strips are arranged so as to be offset in the area between each pair of transverse strip structures in the circumferential direction, thus improving even more the detection of the rotational position of the guide wire.
In a further development of the invention, at least one of the longitudinal marking strips has the shape of a wavy line or zigzag, as a result of which the longitudinal marking strip also supports the detection of the axial position of the guide wire. In an additional embodiment of this technique at least two longitudinal marking strips exhibit different wavy lines or zigzags in the different axial areas between the respective transverse strip structures, a feature that additionally facilitates the detection of the axial position of the guide wire.
Advantageous embodiments of the invention are shown in the drawings and are described below.